package top.plgxs.basic.one;

import java.util.ArrayList;
import java.util.List;

/**
 * <p> 泛型 </p>
 *
 * @author Stranger.
 * @since 2022/9/8 15:58
 */
public class Generics {
    class A{}
    class B extends A {}
    class C extends A {}
    class D extends B {}

    public static void main(String[] args) {

        List<A> a = null;
        List listA = a;
//        List<A> listB = new ArrayList<B>();
        List<?> listC = new ArrayList<Object>();
        List<? extends B> listD = new ArrayList<D>();
        List<? extends A> aE;
//        List<A> listE = new ArrayList();
//        List<Object> o;
//        List listF = o;


    }

}
